Consumers desire stronger, long lasting fragrance from their laundered items. However, consumers also dislike overly strong perfume smell. The problem is how to control the delivery of perfume over multiple wash stages such that the perfume is not too weak or too strong.
Consumers evaluate perfume intensity at numerous stages of a laundry process, beginning with the moment the bottle is opened through to wearing the laundered clothes. Intermediate stages include when wet laundry is removed from the washing machine, whilst the washed items are drying in the air, during ironing and whilst the dry items are in storage. Also of increasing importance to consumers is the so-called perfume bloom, which is fragrance in a room arising from laundered items, which are drying.
Free (i.e. non-encapsulated) perfume oil provides an initial flush of fragrance that quickly dissipates. Whilst this is useful from the bottle, it is too weak during wearing of the laundered items. Much of the free perfume in laundry formulations is washed away with the wash water; free perfume cannot, therefore, satisfactorily deliver specific perfume notes at the different key stages.
In recent years, delivery of specific perfume notes at different key stages has been achieved by the use of encapsulated perfumes. Encapsulated technologies are known for use in laundry products. Such technologies provide enhanced fragrance delivery over conventional free perfume oil by overcoming the issue of perfume loss during the drying process by protecting the perfume in the capsule. Encapsulation also ensures that perfume is released at the optimal time to enable the provision of a perceivable benefit to the wearer of laundered garments. Examples of the mode of action of encapsulates include: shear sensitive action, where the perfume core is released in response to mechanical rupture of the encapsulate, and diffusive action, wherein perfume is released by diffusion through the outer wall of the encapsulate. Some encaps are capable of both release mechanisms. One type of capsule that has been used in laundry compositions has a melamine formaldehyde shell and a perfume core. Release of perfume from melamine formaldehyde capsules is friction based, the benefit becoming apparent after a rubbing process is applied to the treated fabric. This benefit is provided by a boost in perfume intensity during wear.
However, consumers desire a perfume release profile across multiple stages, not just one particular stage. We have determined that a linear release profile across the whole of the laundry process is a strong consumer want.
EP2087089 (P&G) and EP2094828 (Appleton Papers) disclose compositions comprising one or more core/shell particles having a volume weighted fracture strength of from 0.8 to 1.8 MPa. WO2008/066773 (P&G) and WO2008/063635 (Appleton Papers) disclose compositions comprising one or more core/shell particles, selected from the group consisting of Type 1 particles, Type 2 particles, Type 3 particles, Type 4 particles and mixtures thereof, which are defined by fracture strengths ranging from 0.5 to 16 MPa.
WO 2011/075556 (P&G) discloses fabric softeners containing a) a mixture of cross-linked melamine formaldehyde encapsulates and b) a material adjunct, which may be a fabric softener.
WO 2011/094681 (P&G) discloses fabric softening compositions comprising:    (a) a fabric softening active; (b) a first microcapsule encapsulating a first perfume, comprising 76% to 96% of perfume ingredients having a b.p. greater than 250° C. and a Log P greater than 2. 5; (c) a second microcapsule encapsulating a second perfume, which comprises 43% to 63% of perfume ingredients having a b.p. greater than 250° C. and a Log P greater than 2. 5; (d) wherein the weight ratio of the first to the second encapsulates is 50:50 to 70:30; and an optional free perfume, which is different from the first and second perfumes.
We have now found that the inclusion of a mixture of encaps having different release profiles significantly increases the perfume perception during multiple stages of a laundry process.